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Method for producing acrylic fiber

An acrylonitrile-based, acrylonitrile-based technology, applied in the field of preparation of spinning solutions for the production of acrylonitrile-based fibers, can solve problems such as high energy costs, incompatible functional operations, and incompatible industrial applications

Active Publication Date: 2018-07-27
MONTEFIBRE MAE TECH SRL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0015] However, this is not an easy method to implement, and in fact, the optimal solvent power of DMSO already at room temperature causes partial dissolution of the surface of the polymer particles in powder form, with the result that the polymer particles tend to stick to each other, forming insoluble Aggregates and insoluble gels (as described in US4403055), which make proper and economical operation of such industrial processes impossible
[0016] The use of DMSO in the batch process as solvent for polyacrylonitrile-based polymers for the spinning solution has in fact significant disadvantages: it leads to the formation of gels and insoluble aggregates and thus clogs the filters of the device in a very rapid time, which Incompatible with proper functional operation of industrial production lines
However, this method has various disadvantages and contraindications, mainly the time required for the slow addition of the powdered polymer to the solvent under agitation is very lengthy, US4403055 shows a time of about 90 minutes in Example 1, This is incompatible with industrial applications and also requires removal of relevant quantities of water by vacuum heating, again requiring long periods of time
In addition to being extremely time-consuming, these methods obviously also imply high energy costs

Method used

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  • Method for producing acrylic fiber

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0054] High molecular weight acrylonitrile copolymer consisting of acrylonitrile (96% by weight relative to the total weight of the polymer) and pairs of methyl acrylate-itaconic acid (4% by weight relative to the total weight of the polymer) (MW n =75,000-100,000) of dissolution

[0055] The polymer was dispersed in a DMSO / water 95 / 5 solution maintained at a temperature of 5°C.

[0056] Dissolution of polymers in solvent solutions is carried out in industrial lines for the production of spinning solutions of acrylonitrile polymers. The production line consists of the following:

[0057] - storage silos for acrylonitrile polymers;

[0058] - "loss in weight" dosage units for continuous polymer flow;

[0059] - Prismatic column of mixed polymer and solvent (reference above figure 1 describe);

[0060] - collection tank for solvent-polymer suspension (slurry);

[0061] - gear pumps for transferring slurry;

[0062] - a tube bundle exchanger forming a spinning solution (s...

Embodiment 2

[0096] Embodiment 2 (comparison)

[0097] High molecular weight acrylonitrile copolymer consisting of acrylonitrile (96% by weight relative to the total weight of the polymer) and pairs of methyl acrylate-itaconic acid (4% by weight relative to the total weight of the polymer) (MW n =75,000-100,000) of dissolution

[0098] The polymer was dispersed in 100% DMSO maintained at a temperature of 20°C.

[0099] The dissolution of the polymer in the solvent solution was carried out in the same industrial line as used in Example 1.

[0100] The dissolution conditions of the polymer in the solvent solution are as follows:

[0101] - polymer flow rate of 250kg / h at room temperature;

[0102] - using a cooling unit, maintaining a flow rate of 1000 kg / h of solvent (DMSO 100%) at T = 20°C;

[0103] - the temperature of the solution at the outlet of the heat exchanger: 88 °C;

[0104] - Temperature of the solution at the outlet of the cooling exchanger: 70°C.

[0105] The viscosity of...

Embodiment 3

[0110] Medium molecular weight acrylonitrile copolymers (MW n =40,000-55,000) of dissolution

[0111] The polymer was dissolved in a solution of DMSO / water 95 / 5 maintained at a temperature of 5°C.

[0112] The spinning dope thus produced was characterized by a viscosity at 80°C of about 198 poise. Using a "ROTOVISCO" Haake rotational viscometer with a MCV2 cylindrical rotor with a thermostat adjustment unit, and also using a Hoppler viscometer, to control the falling time of a steel ball in a polymer solution with a viscosity of 410 poise at 50°C, the Measurement of viscosity.

[0113] In the same industrial line for the production of spinning solutions of acrylonitrile polymers as used in Example 1, the dissolution of the polymers in the solvent solution was carried out.

[0114] The dissolution conditions of the polymer in the solvent solution are as follows:

[0115] - polymer flow rate of 250kg / h at room temperature;

[0116] - using a cooling group to maintain a flow...

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Abstract

The invention discloses a method for preparing a homogeneous spinning solution for producing acrylonitrile fibers. The method comprises the following steps: i) heating acrylonitrile powder homopolymer or copolymer at a temperature of 5°C-10°C mixed with 94.5 / 5.5-97 / 3% w / w DMSO / water mixture, preferably at 5°C with 95 / 5 DMSO / water mixture, to prepare a homogeneous suspension, wherein the Spray the stream of DMSO / water solvent on the stream of mixed powdered homopolymer or copolymer of acrylonitrile and carry out said mixing in the time of 5-30 minutes; ii) in the time of 0.5-30 minutes, at 70 ℃- The homogeneous suspension from step i) is heated at a temperature of 150° C. until the homopolymer or copolymer is completely dissolved and a homogeneous solution is formed. This spinning solution is then sent into a storage tank or fed into a spinning line.

Description

technical field [0001] The present invention relates to a process for the production of acrylic fibers, in particular to a process for the preparation of spinning solutions for the production of acrylic fibers. [0002] More specifically, the present invention relates to the field of production of acrylic fibers, comprising the preparation of polymers starting from acrylonitrile or mainly from acrylonitrile (90-99% by weight relative to the total weight of the polymer) and one or more A copolymer composed of a comonomer (commonly used in an amount of 1-10 wt% relative to the total weight of the polymer). [0003] Preferred comonomers are: neutral vinyl molecules such as methyl acrylate, methyl methacrylate, vinyl acetate, acrylamide and similar compounds; or molecules carrying one or more acid groups such as acrylic acid , itaconic acid sulfonated styrenes and similar compounds; or other comonomers that can impart different physicochemical characteristics to the material. ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): D01F6/38D01D1/02
CPCD01D1/02D01D4/06D01D5/06D01F6/18D01F6/38C08L33/20C08L2203/12C08L2201/54D10B2321/10B01F21/20B01F25/42D01F1/02
Inventor F·弗兰克兰茨P·高佐M·玛林提R·普鲁瑟皮欧
Owner MONTEFIBRE MAE TECH SRL